Thursday, October 13, 2011

The real danger from the Tappan Zee Bridge

Last month, Planet Money did a great report on the Tappan Zee Bridge. (For the short attention span crowd, here's the five-minute version.) David Kestenbaum noticed that the bridge was built in a really stupid place, at the widest point in the entire river, on soft ground far above the bedrock. I had kind of noticed that too, but I assumed that the people involved knew what they were doing. Ha!

When Kestenbaum started asking around he found out that no, by engineering criteria just about any other spot on the river was better for a bridge. The Tappan Zee Bridge was built where it was for political reasons.

Like most political fights, it was about power in the form of money. In this case it was the money from tolls. Essentially, the law that created the Port Authority of New York and New Jersey gave it a monopoly on the toll revenue from all bridges and tunnels that crossed between New York and New Jersey, within a 25-mile radius of the Statue of Liberty.

Governor Thomas Dewey (the one who didn't defeat Truman) wanted to build a big highway from the Bronx to Buffalo that would reunite the state. It would have to cross the Hudson at some point, and he figured that the excess toll revenue from that crossing could fund the construction of the rest of the highway - a highway now known as the Thomas E. Dewey Thruway.

If the State built the bridge too far north, it would not attract enough toll money to fund the highway. If they built it too far south, the Port Authority would get the money and spend it all on PATH trains and skyscrapers. The optimal place to put it according to the engineering criteria was right by Bear Mountain - but there was already a bridge there, not to mention a popular state park. So Dewey had it built just outside the Port Authority's territory.

Remember how I said "excess toll revenue"? That means the money left after the Thruway Authority sets aside funds for bridge maintenance. Well, the size of that "excess" is a matter of opinion, it turns out, if you look at the Thruway's "Budget Book." Toll revenues have always exceeded maintenance costs, but maintenance eats up a larger chunk every year.

Let's make something perfectly clear here: this is not going to be a repeat of the I-35W Bridge disaster in Minneapolis. Nobody thinks the bridge is going to fall down. It's not structurally deficient, it's "functionally obsolete." People whine about the crash rate, but just as with the BQE in Brooklyn, it would be a lot safer (and undergo less wear and tear) if the Thruway Authority wasn't trying to squeeze seven lanes of traffic onto a bridge where there's really only room for six.

The rising costs to maintain the bridge have meant that each year a smaller proportion of the tolls can be used to maintain and operate the rest of the sprawling system, and to pay the interest on the bonds that have been issued to fund projects up front. As with the Port Authority itself, the Thruway Authority has been used as a piggy bank for the State, taking on additional responsibilities like the untolled Cross-Westchester Expressway, the untolled Interstate 84 (returned to the State last year) and the Erie Canal, and allowing the State to close toll plazas, making sections of the Thruway in Albany and Buffalo free for local travel and making Syracuse jealous.

Now before doing a few calculations tonight, I've never heard the simple fact that even though the Thruway spends $30 million a year to maintain the bridge, and that number is rising every year, the tolls bring in $50 million. It's not the bridge budget that's in danger, it's the millions of toll dollars that get sent upstate and to Wall Street. Conceivably, the Thruway Authority could simply keep using the tolls to pay bridge maintenance, and the rest of the Thruway can go whistle. Maintaining a badly designed bridge in an ill-chosen location might not be the best use of the money, but building a new, wider bridge in the same place sure ain't.